We need to practice our equalization techniques to prevent damage to our bodies which contain air spaces that are exposed to pressure changes during freediving or scuba diving. These pressure changes must be compensated in order to avoid pressure-related injury or barotrauma. There are several techniques of pressure equalization in the facial air cavities and the compensation of the mask. It is important to remember that compensation is a very individual thing, there is no ‘correct’ amount of pressure equalization maneuvers for a certain depth. Many people use different combinations of the techniques described below with their own maneuvers. For example, I use a technique pushing the jaw outwards and downwards while swallowing to equalize. It is important to give everything a try in the water to really know what works for you and what doesn’t.
So here are a few methods you can try.
The Valsalva maneuver, named after Antonio Valsalva who was the first to record the pressurization of the middle ears in the 1700s, is performed by forcibly exhaling against closed lips and pinched nose. This forces air from the lungs into the middle ear, if the Eustachian tube is open. This is the most common technique of compensation among freedivers, however, this technique is only effective in depths of up to -30 meters. In greater depths, there simply isn’t enough air left in the lungs to equalize the pressure in the ears and sinuses. This technique also causes the contraction of the lung muscles – an oxygen-consuming practice.
The Frenzel Maneuver- Herman Frenzel was the Luftwaffe commander who taught this technique to dive-bomber pilots during World War II. The technique is to close off the vocal cords, as though you are about to lift a heavyweight. The nostrils are pinched closed and an effort is made to make a ‘k’ or a ‘guh’ sound. By doing this you raise the back of the tongue and the ‘Adam’s Apple’ will elevate. This turns the tongue into a piston, pushing air up. This maneuver can be done relatively effortlessly and is not as oxygen consuming as the valsalva maneuver. It can be repeated many times quickly underwater and is effective in depths of up to -80 meters.
The BTV (VTO) Maneuver- Stands for ‘Beance Tubaire Volontaire’. In the 1950s the French navy developed a technique for middle ear equalization called ‘Voluntary Tubal Opening’. This technique is difficult to teach and only approximately 30% of taught can perform it reliably. Muscles of the soft palate are contracted while upper throat muscles are employed to pull the Eustachian tube open. This technique is similar to the events that happen in the back of your throat at the end of a yawn. It is also similar to wiggling your ears and some people seem to be born with the talent. For a manual of BTV see the BTV (VTO) manual.
The Wet Equalization Maneuver- performed by allowing water to flood the sinuses – by doing this the freediver cancels the need for air in order to equalize the pressure in the middle ear and sinuses. The freediver may chose to use the Frenzel maneuver in order to push water into the inner ear to reduce the air space further. This technique requires a lot of training to prevent aspiration of water into the lungs and drowning. The practice of this technique may cause infection of the ear and sinuses.
The Toynbee Maneuver- Joseph Toynbee lived in the 1800s and was the first to identify the crackling sound present in one’s head with the anatomical opening of the Eustachian tubes during swallowing. His technique is to pinch nostrils shut while swallowing. The muscles in the back of the throat pull open the Eustachian tube and allow air to equalize if a gradient is present. Using this technique during a freedive, there is very little or no margin for error if the Eustachian tube doesn’t equalize on the first effort.
Equalization Of The Mask- To equalize the pressure in the mask the freediver must simply blow a small amount of air out of his nose into the mask (This is why a mask with a nose pocket so important for freediving). Usually, when performing the Valsalva or Frenzel maneuvers, some air ‘leaks’ out of the nose into the mask during or right after the equalization of the ears and thus equalizing the mask. Equalizing the mask becomes trickier at greater depths when the air volume in the lungs decreases. Many freedivers who dive to great depths don’t use a mask during the dive or use Fluid Goggles, which are filled with liquid and do not need to be equalized.
If you wan to know more about the important art of equalisation techniques then come and see us at Big Blue Freediving and we’ll have you filling up those spaces in seconds!